RELATED APPLICATION
BACKGROUND INFORMATION
Field of the Disclosure
[0002] The present invention relates to novel electroactive compounds. The invention further
relates to electronic devices having at least one active layer comprising such an
electroactive compound.
Description of the Related Art
[0003] In organic photoactive electronic devices, such as organic light emitting diodes
("OLED"), that make up OLED displays, the organic active layer is sandwiched between
two electrical contact layers in an OLED display. In an OLED the organic photoactive
layer emits light through the light-transmitting electrical contact layer upon application
of a voltage across the electrical contact layers.
[0004] It is well known to use organic electroluminescent compounds as the active component
in light-emitting diodes. Simple organic molecules, conjugated polymers, and organometallic
complexes have been used. Devices that use photoactive materials frequently include
one or more charge transport layers, which are positioned between a photoactive (e.g.,
light-emitting) layer and a contact layer (hole-injecting contact layer). A device
can contain two or more contact layers. A hole transport layer can be positioned between
the photoactive layer and the hole-injecting contact layer. The hole-injecting contact
layer may also be called the anode. An electron transport layer can be positioned
between the photoactive layer and the electron-injecting contact layer. The electron-injecting
contact layer may also be called the cathode.
[0005] There is a continuing need for charge transport materials for use in electronic devices.
WO 02/051958 describes electroactive polyarylamine-type compositions which have ion chelating
side chains such as polyethoxy glycol groups.
SUMMARY
[0006] There is provided a compound having Formula I or Formula II:

wherein:
Ar1 is the same or different at each occurrence and is selected from the group consisting
of a single bond and an arylene;
Ar2 is the same or different at each occurrence and is an aryl group;
Ar3 is the same or different at each occurrence and is selected from the group consisting
of a single bond and an arylene;
R1 is the same or different at each occurrence and is selected from the group consisting
of H, D, aryl groups, alkyl groups, silyl groups, siloxane groups, and fluoroalkyl
groups, or the two R1 groups may be joined together to form an aliphatic ring having 5-10 carbons;
R2 is the same or different at each occurrence and is selected from the group consisting
of D, aryl groups, alkyl groups, silyl groups, siloxane groups, fluoroalkyl groups,
alkoxy groups, and fluoroalkoxy groups;
M is the same or different at each occurrence and is a conjugated moiety;
a is the same or different at each occurrence and is an integer from 0 to 5;
n is an integer equal to or greater than 2; and x and y are mole fractions such that
x + y = 1.0, with the provisos that x and y are not zero, and that the compound is
not

where n is an integer greater than 1;

where n is an integer greater than 1; or

[0007] There is also provided an electronic device having at least one layer comprising
above compound having Formula I or Formula II.
[0008] The foregoing general description and the following detailed description are exemplary
and explanatory only and are not restrictive of the invention, as defined in the appended
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Embodiments are illustrated in the accompanying figures to improve understanding
of concepts as presented herein.
[0010] FIG. 1 includes an illustration of one example of an organic electronic device.
[0011] Skilled artisans appreciate that objects in the figures are illustrated for simplicity
and clarity and have not necessarily been drawn to scale. For example, the dimensions
of some of the objects in the figures may be exaggerated relative to other objects
to help to improve understanding of embodiments.
DETAILED DESCRIPTION
[0012] There is provided a compound having Formula I or Formula II:

wherein:
Ar1 is the same or different at each occurrence and is selected from the group consisting
of a single bond and an arylene;
Ar2 is the same or different at each occurrence and is an aryl group;
Ar3 is the same or different at each occurrence and is selected from the group consisting
of a single bond and an arylene;
R1 is the same or different at each occurrence and is selected from the group consisting
of H, D, aryl groups, alkyl groups, silyl groups, siloxane groups and, fluoroalkyl
groups, or the two R1 groups may be joined together to form an aliphatic ring having 5-10 carbons;
R2 is the same or different at each occurrence and is selected from the group consisting
of D, aryl groups, alkyl groups, silyl groups, siloxane groups, fluoroalkyl groups,
alkoxy groups, and fluoroalkoxy groups;
M is the same or different at each occurrence and is a conjugated moiety;
a is the same or different at each occurrence an integer from 0 to 5;
n is an integer equal to or greater than 2; and
x and y are mole fractions such that x + y = 1.0, with the provisos that x and y are
not zero, and that the compound is not

where n is an integer greater than 1;

where n is an integer greater than 1; or

[0013] There is also provided an electronic device having at least one layer comprising
a compound having Formula I or Formula II.
[0014] Many aspects and embodiments have been described above and are merely exemplary and
not limiting. After reading this specification, skilled artisans appreciate that other
aspects and embodiments are possible without departing from the scope of the invention.
[0015] Other features and benefits of any one or more of the embodiments will be apparent
from the following detailed description, and from the claims. The detailed description
first addresses Definitions and Clarification of Terms followed by the Electroactive
Compound, the Electronic Device, and finally Examples.
1. Definitions and Clarification of Terms
[0016] Before addressing details of embodiments described below, some terms are defined
or clarified.
[0017] As used herein, the term "alkyl" includes branched and straight-chain saturated aliphatic
hydrocarbon groups. Unless otherwise indicated, the term is also intended to include
cyclic groups. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl,
isobutyl, secbutyl, tertbutyl, pentyl, isopentyl, neopentyl, cyclopentyl, hexyl, cyclohexyl,
isohexyl and the like. The term "alkyl" further includes both substituted and unsubstituted
hydrocarbon groups. In some embodiments, the alkyl group may be mono-, di- and tri-substituted.
One example of a substituted alkyl group is trifluoromethyl. Other substituted alkyl
groups are formed from one or more of the substituents described herein. In certain
embodiments alkyl groups have 1 to 20 carbon atoms. In other embodiments, the group
has 1 to 6 carbon atoms. The term is intended to include heteroalkyl groups. Heteroalkyl
groups may have from 1-20 carbon atoms.
[0018] The term "aryl" means an aromatic carbocyclic moiety, which may be a single ring
(monocyclic) or multiple rings (bicyclic, or more) fused together or linked covalently.
Any suitable ring position of the aryl moiety may be covalently linked to the defined
chemical structure. Examples of aryl moieties include, but are not limited to, phenyl,
1-naphthyl, 2-naphthyl, dihydronaphthyl, tetrahydronaphthyl, biphenyl. anthryl, phenanthryl,
fluorenyl, indanyl, biphenylenyl, acenaphthenyl, acenaphthylenyl, and the like. In
some embodiments, aryl groups have 6 to 60 carbon atoms; in some embodiments 6 to
48 carbon atoms. The term is intended to include heteroaryl groups. Heteroaryl groups
may have from 4-50 carbon atoms.
[0019] The term "alkoxy" is intended to mean the group -OR, where R is alkyl.
[0020] The term "aryloxy" is intended to mean the group -OR, where R is aryl.
[0021] Unless otherwise indicated, all groups can be substituted or unsubstituted. An optionally
substituted group, such as, but not limited to, alkyl or aryl, may be substituted
with one or more substituents which may be the same or different. Suitable substituents
include alkyl, aryl, nitro, cyano, -N(R
7)(R
8), halo, hydroxy, carboxy, alkenyl, alkynyl, cycloalkyl, heteroaryl, alkoxy, aryloxy,
heteroaryloxy, alkoxycarbonyl, perfluoroalkyl, perfluoroalkoxy, arylalkyl, silyl,
siloxane, thioalkoxy, -S(O)
2-N(R')(R"), - C(=O)-N(R')(R"), (R')(R")N-alkyl, (R')(R")N-alkoxyalkyl, (R')(R")N-alkylaryloxyalkyl,
-S(O)
s-aryl (where s=0-2) or -S(0)
s-heteroaryl (where s=0-2). Each R' and R" is independently an optionally substituted
alkyl, cycloalkyl, or aryl group. R' and R", together with the nitrogen atom to which
they are bound, can form a ring system in certain embodiments. Substituents may also
be crosslinking groups.
[0022] The term "charge transport," when referring to a layer, material, member, or structure
is intended to mean such layer, material, member, or structure facilitates migration
of such charge through the thickness of such layer, material, member, or structure
with relative efficiency and small loss of charge. Hole transport materials facilitate
positive charge; electron transport material facilitate negative charge. Although
light-emitting materials may also have some charge transport properties, the term
"charge transport layer, material, member, or structure" is not intended to include
a layer, material, member, or structure whose primary function is light emission.
[0023] The term "compound" is intended to mean an electrically uncharged substance made
up of molecules that further include atoms, wherein the atoms cannot be separated
from their corresponding molecules by physical means without breaking chemical bonds.
The term is intended to include oligomers and polymers.
[0024] The term "crosslinkable group" or "crosslinking group" is intended to mean a group
than can lead to crosslinking via thermal treatment or exposure to radiation. In some
embodiments, the radiation is UV or visible.
[0025] The term "electroactive" as it refers to a layer or a material, is intended to indicate
a layer or material which electronically facilitates the operation of the device.
Examples of active materials include, but are not limited to, materials which conduct,
inject, transport, or block a charge, where the charge can be either an electron or
a hole, or materials which emit radiation or exhibit a change in concentration of
electron-hole pairs when receiving radiation. Examples of inactive materials include,
but are not limited to, planarization materials, insulating materials, and environmental
barrier materials.
[0026] The prefix "fluoro" is intended to indicate that one or more hydrogens in a group
has been replaced with fluorine.
[0027] The prefix "hetero" indicates that one or more carbon atoms has been replaced with
a different atom. In some embodiments, the heteroatom is O, N, S, or combinations
thereof.
[0028] The term "oxyalkyl" is intended to mean a heteroalkyl group having one or more carbons
replaced with oxygens. The term includes groups which are linked via an oxygen.
[0029] The term "photoactive" is intended to mean to any material that exhibits electroluminescence
or photosensitivity.
[0030] The term "silyl" refers to the group R
3Si-, where R is H, D, C1-20 alkyl, fluoroalkyl, or aryl. In some embodiments, one
or more carbons in an R alkyl group are replaced with Si. In some embodiments, the
silyl groups are (hexyl)
2Si(Me)CH
2CH
2Si(Me) 2- and [CF
3(CF
2)
6CH
2CH
2]
2SiMe- .
[0031] The term "siloxane" refers to the group (RO)
3Si-, where R is H, D , C1-20 alkyl, or fluoroalkyl.
[0032] The phrase "adjacent to," when used to refer to layers in a device, does not necessarily
mean that one layer is immediately next to another layer. On the other hand, the phrase
"adjacent R groups," is used to refer to R groups that are next to each other in a
chemical formula (i.e., R groups that are on atoms joined by a bond).
[0033] As used herein, the terms "comprises," "comprising," "includes," "including," "has,"
"having" or any other variation thereof, are intended to cover a non-exclusive inclusion.
For example, a process, method, article, or apparatus that comprises a list of elements
is not necessarily limited to only those elements but may include other elements not
expressly listed or inherent to such process, method, article, or apparatus. Further,
unless expressly stated to the contrary, "or" refers to an inclusive or and not to
an exclusive or. For example, a condition A or B is satisfied by any one of the following:
A is true (or present) and B is false (or not present), A is false (or not present)
and B is true (or present), and both A and B are true (or present).
[0034] Also, use of "a" or "an" are employed to describe elements and components described
herein. This is done merely for convenience and to give a general sense of the scope
of the invention. This description should be read to include one or at least one and
the singular also includes the plural unless it is obvious that it is meant otherwise.
[0036] Unless otherwise defined, all technical and scientific terms used herein have the
same meaning as commonly understood by one of ordinary skill in the art to which this
invention belongs. Although methods and materials similar or equivalent to those described
herein can be used in the practice or testing of embodiments of the present invention,
suitable methods and materials are described below. In case of conflict, the present
specification, including definitions, will control. In addition, the materials, methods,
and examples are illustrative only and not intended to be limiting.
[0037] To the extent not described herein, many details regarding specific materials, processing
acts, and circuits are conventional and may be found in textbooks and other sources
within the organic light-emitting diode display, photodetector, photovoltaic, and
semiconductive member arts.
2. Electroactive Compound
[0038] The compound described herein has Formula I or Formula II:

wherein:
Ar1 is the same or different at each occurrence and is selected from the group consisting
of a single bond and an arylene;
Ar2 is the same or different at each occurrence and is an aryl group;
Ar3 is the same or different at each occurrence and is selected from the group consisting
of a single bond and an arylene;
R1 is the same or different at each occurrence and is selected from the group consisting
of H, D, aryl groups, alkyl groups, silyl groups, siloxane groups, and fluoroalkyl
groups, or the two R1 groups may be joined together to form an aliphatic ring having 5-10 carbons;
R2 is the same or different at each occurrence and is selected from the group consisting
of D, aryl groups, alkyl groups, silyl groups, siloxane groups, fluoroalkyl groups,
alkoxy groups, and fluoroalkoxy groups;
M is the same or different at each occurrence and is a conjugated moiety;
a is the same or different at each occurrence an integer from 0 to 5;
n is an integer equal to or greater than 2; and
x and y are mole fractions such that x + y = 1.0, with the provisos that x and y are
not zero and that the compound is not

where n is an integer greater than 1;

where n is an integer greater than 1; or

[0039] In the formulae, a bond drawn through the center of a fused ring system indicates
that the substituent can be bonded to any available carbon in the fused ring.
[0040] The compounds of Formula I and Formula II have a 1, 1'-binaphthyl core which has
aryl amino groups further linked through a meta linkage. The compounds have good hole
transport properties. When these materials are used in the hole transport layer of
OLEDs, the resulting devices can have good efficiency and lifetime. In some embodiments,
the compounds can be used as hosts for light-emitting materials in light-emitting
layers of devices.
[0041] In some embodiments, the compound has Formula la with a 3,3'-binaphthyl linkage.

[0042] In some embodiments, the compound has Formula Ib with a 4,4'-binaphthyl linkage.

[0043] In some embodiments, the compound has Formula Ic with a 5,5'-binaphthyl linkage.

[0044] In some embodiments, the compound has Formula Id with a 6,6'-binaphthyl linkage.

[0045] In some embodiments, the compound has Formula le with a 7,7'-binaphthyl linkage.

[0046] In Formulae Ia-e:
Ar1, Ar2, Ar3, R1, R2 and n are as defined above;
b is the same or different at each occurrence and is an integer from 0 to 4;
c is the same or different at each occurrence and is an integer from 0 to 1;
d is the same or different at each occurrence and is an integer from 0 to 2; and
e is the same or different at each occurrence and is an integer from 0 to 3.
[0048] In Formulae IIa-e:
Ar1, Ar2, Ar3, R1, R2, and M are as defined above;
b is the same or different at each occurrence and is an integer from 0 to 4;
c is the same or different at each occurrence and is an integer from 0 to 1;
d is the same or different at each occurrence and is an integer from 0 to 2; and
e is the same or different at each occurrence and is an integer from 0 to 3.
[0049] In some embodiments, Ar
1 has Formula III

where:
R3 is the same or different at each occurrence and is selected from the group consisting
of D, alkyl, alkoxy, siloxane and silyl;
b is the same or different at each occurrence and is an integer from 0-4; and
m is the same or different at each occurrence and is an integer from 1 to 6.
[0050] In some embodiments, at least one of one b is not zero. In some embodiments, m =
1-3.
[0051] In some embodiments, Ar
1 is selected from the group consisting of a single bond, phenylene, p-biphenylene,
p-terphenylene, naphthylene, phenylenenaphthylene, and naphthylenephenylene. In some
embodiments, Ar
1 is selected from the group consisting of phenylene and biphenylene.
[0052] In some embodiments, Ar
2 has Formula IV

where:
R3 is the same or different at each occurrence and is selected from the group consisting
of alkyl, alkoxy, siloxane and silyl;
a is an integer from 0 to 5;
b is the same or different at each occurrence and is an integer from 0 to 4; and
m is the same or different at each occurrence and is an integer from 1 to 6.
[0053] In some embodiments of Formula IV, at least one of one a and b is not zero. In some
embodiments, m = 1-3. In some embodiments, Ar
2 is selected from the group consisting phenyl, biphenyl, terphenyl, and naphthyl.
[0054] In some embodiments, Ar
3 has Formula III, as defined above.
[0055] In some embodiments of Formula III, at least one b is not zero. In some embodiments,
m = 1-3. In some embodiments, Ar
3 is selected from the group consisting of a single bond, phenylene, biphenylene, and
naphthylene. In some embodiments, Ar
3 is selected from the group consisting of phenylene and biphenylene.
[0056] Any of Ar
1, Ar
2 and Ar
3, when not a single bond, may be substituted at any position. The substituents may
be present to improve one or more physical properties of the compound, such as solubility.
In some embodiments, the substituents are selected from the group consisting of D,
alkyl groups, silyl groups, siloxane groups, and alkoxy groups. In some embodiments,
the groups have from 1-12 carbon atoms. In some embodiments, adjacent alkyl groups
are joined together to form a nonaromatic ring. In some embodiments, there is at least
one substituent which includes a crosslinkable group. In some embodiments, crosslinking
substituents are present on at least one Ar
2. Examples of crosslinkable groups include, but are not limited to vinyl, acrylate,
perfluorovinylether, 1-benzo-3,4-cyclobutane, siloxane, cyanate groups, cyclic ethers
(epoxides), cycloalkenes, and acetylenic groups. In one embodiment, the crosslinkable
group is vinyl.
[0057] In some embodiments, R
1 is selected from an alkyl group having 1-12 carbon atoms.
[0058] In some embodiments, R
2 is selected an alkyl group having 1-12 carbon atoms and an alkoxy group having 1-12
carbon atoms.
[0059] In some embodiments, a and b are selected from 0 and 1. In some embodiments, a =
b = 0.
[0060] In some embodiments, n=1 and the compound is not polymeric. In some embodiments,
n is 2 or greater and the compound is an oligomer or polymer. In some embodiments,
n is greater than 20.
[0061] Formula II represents a copolymer in which there is at least one other conjugated
moiety. In some embodiments, x is at least 0.4. In some embodiments, x is in the range
of 0.4 to 0.6. The copolymers can be random, alternating, or block copolymers. In
some embodiments, M is an aromatic unit having triarylamine units. In some embodiments,
M is an aromatic group. In some embodiments, M is an aromatic unit having a crosslinkable
substituent. The amount of M having a crosslinkable substituent is generally between
4 and 20 mole percent.
[0062] When R
1 is not H or D, the substituted binaphthyl group introduces non-planarity into the
backbone of the compound having Formula I or Formula II. The first naphthyl group
is oriented in a plane that is different from the second naphthyl group to which it
is linked. Because of the non-planarity, the compounds are chiral. In general, they
are formed as racemic mixtures. Some non-limiting examples of compounds having Formula
I include Compounds A - D below.
Compound A
[0063]

Compound B:
[0064]

Compound C:
[0065]

Compound D:
[0066]

[0067] The new compounds can be made using any technique that will yield a C-C or C-N bond.
A variety of such techniques are known, such as Suzuki, Yamamoto, Stille, and other
transition metal catalyzed coupling reactions. The compounds can be formed into layers
using solution processing techniques. The term "layer" is used interchangeably with
the term "film" and refers to a coating covering a desired area. The term is not limited
by size. The area can be as large as an entire device or as small as a specific functional
area such as the actual visual display, or as small as a single sub-pixel. Layers
and films can be formed by any conventional deposition technique, including vapor
deposition, liquid deposition (continuous and discontinuous techniques), and thermal
transfer. Continuous deposition techniques, include but are not limited to, spin coating,
gravure coating, curtain coating, dip coating, slot-die coating, spray coating, and
continuous nozzle coating. Discontinuous deposition techniques include, but are not
limited to, ink jet printing, gravure printing, and screen printing. When crosslinking
groups are present, the films can be heated and/or treated with UV light to form crosslinked
films. The crosslinked films are more robust to additional processing steps and generally
are not soluble in processing solvents.
[0068] The new compounds described herein have can be used as hole transport materials,
as photoactive materials, and as hosts for photoactive materials. The new compounds
have hole mobilities and HOMO/LUMO energies similar to efficient small molecule hole
transport compounds such as N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine
(TPD) and N,N'-bis(naphthalen-1-yl)-N,N'-bis-(phenyl)benzidine (α-NPB). Compounds
such as TPD and NPD generally must be applied using a vapor deposition technique.
[0069] In some embodiments, the new compounds are useful as hosts for photoactive materials.
3. Electronic Devices
[0070] Organic electronic devices that may benefit from having one or more layers comprising
at least one compound as described herein include, but are not limited to, (1) devices
that convert electrical energy into radiation (e.g., a light-emitting diode, light
emitting diode display, or diode laser), (2) devices that detect signals through electronics
processes (e.g., photodetectors, photoconductive cells, photoresistors, photoswitches,
phototransistors, phototubes, IR detectors), (3) devices that convert radiation into
electrical energy, (e.g., a photovoltaic device or solar cell), and (4) devices that
include one or more electronic components that include one or more organic semi-conductor
layers (e.g., a transistor or diode). Other uses for the compositions according to
the present invention include coating materials for memory storage devices, antistatic
films, biosensors, electrochromic devices, solid electrolyte capacitors, energy storage
devices such as a rechargeable battery, and electromagnetic shielding applications.
[0071] One illustration of an organic electronic device structure is shown in Figure 1.
The device 100 has an anode layer 110 and a cathode layer 150, and a photoactive layer
130 between them. Adjacent to the anode is a layer 120 comprising a charge transport
material, for example, a hole transport material. Adjacent to the cathode may be a
charge transport layer 140 comprising an electron transport material. As an option,
devices may use one or more additional hole injection or hole transport layers (not
shown) next to the anode 110 and/or one or more additional electron injection or electron
transport layers (not shown) next to the cathode 150.
[0072] As used herein, the term "photoactive" refers to a material that emits light when
activated by an applied voltage (such as in a light-emitting diode or light-emitting
electrochemical cell), or responds to radiant energy and generates a signal with or
without an applied bias voltage (such as in a photodetector). In one embodiment, a
photoactive layer is an emitter layer.
[0073] Depending upon the application of the device 100, the photoactive layer 130 can be
a light-emitting layer that is activated by an applied voltage (such as in a light-emitting
diode or light-emitting electrochemical cell), a layer of material that responds to
radiant energy and generates a signal with or without an applied bias voltage (such
as in a photodetector). Examples of photodetectors include photoconductive cells,
photoresistors, photoswitches, phototransistors, and phototubes, and photovoltaic
cells, as these terms are described in
Kirk-Othmer Concise Encyclopedia of Chemical Technology, 4th edition, p.1537, (1999).
[0074] In some embodiments, the hole transport layer 120 comprises at least one new electroactive
compound as described herein.
[0075] In some embodiments, the photoactive layer 130 comprises at least one new electroactive
compound as described herein, wherein the electroactive compound is photoactive.
[0076] In some embodiments, the photoactive layer 130 comprises at least one new electroactive
compound as described herein, wherein the electroactive compound serves as a host
having a photoactive material dispersed therein.
[0077] The other layers in the device can be made of any materials which are known to be
useful in such layers. The anode 110, is an electrode that is particularly efficient
for injecting positive charge carriers. It can be made of, for example materials containing
a metal, mixed metal, alloy, metal oxide or mixed-metal oxide, or it can be a conducting
polymer, and mixtures thereof. Suitable metals include the Group 11 metals, the metals
in Groups 4, 5, and 6, and the Group 8 10 transition metals. If the anode is to be
light-transmitting, mixed-metal oxides of Groups 12, 13 and 14 metals, such as indium-tin-oxide,
are generally used. The anode 110 may also comprise an organic material such as polyaniline
as described in "
Flexible light-emitting diodes made from soluble conducting polymer," Nature vol.
357, pp 477 479 (11 June 1992). At least one of the anode and cathode should be at least partially transparent
to allow the generated light to be observed.
[0078] In some embodiments, the device further comprises a buffer layer between the anode
and the layer comprising the new polymer. The term "buffer layer" is intended to mean
a layer comprising electrically conductive or semiconductive materials and may have
one or more functions in an organic electronic device, including but not limited to,
planarization of the underlying layer, charge transport and/or charge injection properties,
scavenging of impurities such as oxygen or metal ions, and other aspects to facilitate
or to improve the performance of the organic electronic device. Buffer materials may
be polymers, oligomers, or small molecules, and may be in the form of solutions, dispersions,
suspensions, emulsions, colloidal mixtures, or other compositions. The buffer layer
can be formed with polymeric materials, such as polyaniline (PANI) or polyethylenedioxythiophene
(PEDOT), which are often doped with protonic acids. The protonic acids can be, for
example, poly(styrenesulfonic acid), poly(2-acrylamido-2-methyl-1-propanesulfonic
acid), and the like. The buffer layer can comprise charge transfer compounds, and
the like, such as copper phthalocyanine and the tetrathiafulvalene-tetracyanoquinodimethane
system (TTF-TCNQ). In one embodiment, the buffer layer is made from a dispersion of
a conducting polymer and a colloid-forming polymeric acid. Such materials have been
described in, for example, published
U.S. patent applications 2004-0102577,
2004-0127637, and
2005/205860.
[0079] In some embodiments, hole transport layer 120 comprises the new electroactive compound
described herein. In some embodiments, layer 120 comprises other hole transport materials.
Examples of other hole transport materials for layer 120 have been summarized for
example, in
Kirk Othmer Encyclopedia of Chemical Technology, Fourth Edition, Vol. 18, p. 837 860,
1996, by Y. Wang. Both hole transporting molecules and polymers can be used. Commonly used hole transporting
molecules include, but are not limited to: N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine
(TPD), 1,1-bis[(di-4-tolylamino) phenyl]cyclohexane (TAPC), N,N'-bis(4-methylphenyl)-N,N'-bis(4-ethylphenyl)-[1,1'-(3,3'-dimethyl)biphenyl]-4,4'-diamine
(ETPD), tetrakis (3-methylphenyl)-N,N,N',N'-2,5-phenylenediamine (PDA), a-phenyl 4-N,N-diphenylaminostyrene
(TPS), p- (diethylamino)benzaldehyde diphenylhydrazone (DEH), triphenylamine (TPA),
bis[4 (N,N-diethylamino)-2-methylphenyl](4-methylphenyl)methane (MPMP), 1-phenyl-3-[p-(diethylamino)styryl]-5-[p-(diethylamino)phenyl]
pyrazoline (PPR or DEASP), 1,2-trans-bis(9H-carbazol-9-yl)cyclobutane (DCZB), N,N,N',N'
tetrakis(4-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TTB), N,N'-Bis(naphthalen-1-yl)-N,N'-bis-(phenyl)benzidine
(α-NPB), and porphyrinic compounds, such as copper phthalocyanine. Commonly used hole
transporting polymers include, but are not limited to, polyvinylcarbazole, (phenylmethyl)polysilane,
and polyaniline. It is also possible to obtain hole transporting polymers by doping
hole transporting molecules such as those mentioned above into polymers such as polystyrene
and polycarbonate. Buffer layers and/or hole transport layer can also comprise polymers
of thiophene, aniline, or pyrrole with polymeric fluorinated sulfonic acids, as described
in published
US applications 2004/102577,
2004/127637, and
2005/205860.
[0080] Any organic electroluminescent ("EL") material can be used as the photoactive material
in layer 130, including, but not limited to, small molecule organic fluorescent compounds,
fluorescent and phosphorescent metal complexes, conjugated polymers, and mixtures
thereof. Examples of fluorescent compounds include, but are not limited to, chrysenes,
pyrenes, perylenes, rubrenes, coumarins, anthracenes, thiadiazoles, derivatives thereof,
and mixtures thereof. Examples of metal complexes include, but are not limited to,
metal chelated oxinoid compounds, such as tris(8-hydroxyquinolato)aluminum (Alq3);
cyclometalated iridium and platinum electroluminescent compounds, such as complexes
of iridium with phenylpyridine, phenylquinoline, or phenylpyrimidine ligands as disclosed
in
Petrov et al., U.S. Patent 6,670,645 and Published
PCT Applications WO 03/063555 and
WO 2004/016710, and organometallic complexes described in, for example, Published
PCT Applications WO 03/008424,
WO 03/091688, and
WO 03/040257, and mixtures thereof. In some cases the small molecule fluorescent or organometallic
materials are deposited as a dopant with a host material to improve processing and/or
electronic properties. Examples of conjugated polymers include, but are not limited
to poly(phenylenevinylenes), polyfluorenes, poly(spirobifluorenes), polythiophenes,
poly(p-phenylenes), copolymers thereof, and mixtures thereof. The materials may also
be present in admixture with a host material. In some embodiments, the host material
is a hole transport material or an electron transport material. In some embodiments,
the host is the new electroactive compound described herein. In some embodiments,
the ratio of host material to photoactive material is in the range of 5:1 to 20:1;
in some embodiments, 10:1 to 15:1.
[0081] Examples of electron transport materials which can be used in the electron transport
layer 140 and/or the optional layer between layer 140 and the cathode include metal
chelated oxinoid compounds, such as tris(8-hydroxyquinolato)aluminum (AlQ), bis(2-methyl-8-quinolinolato)(p-phenylphenolato)
aluminum (BAlq), tetrakis-(8-hydroxyquinolato)hafnium (HfQ) and tetrakis-(8-hydroxyquinolato)zirconium
(ZrQ); and azole compounds such as 2- (4-biphenylyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole
(PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-t-butylphenyl)-1,2,4-triazole (TAZ), and 1,3,5-tri(phenyl-2-benzimidazole)benzene
(TPBI); quinoxaline derivatives such as 2,3-bis(4-fluorophenyl)quinoxaline; phenanthrolines
such as 4,7-diphenyl-1,10-phenanthroline (DPA) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline
(DDPA); and mixtures thereof.
[0082] The cathode 150, is an electrode that is particularly efficient for injecting electrons
or negative charge carriers. The cathode can be any metal or nonmetal having a lower
work function than the anode. Materials for the cathode can be selected from alkali
metals of Group 1 (e.g., Li, Cs), the Group 2 (alkaline earth) metals, the Group 12
metals, including the rare earth elements and lanthanides, and the actinides. Materials
such as aluminum, indium, calcium, barium, samarium and magnesium, as well as combinations,
can be used. Li-containing organometallic compounds, LiF, and Li
2O can also be deposited between the organic layer and the cathode layer to lower the
operating voltage.
[0083] The choice of materials for each of the component layers is preferably determined
by balancing the goals of providing a device with high device efficiency with device
operational lifetime. Other layers may also be present in the device. There may be
one or more hole injection and/or hole transport layers between the buffer layer and
the organic active layer. There may be one or more electron transport layers and/or
electron injection layers between the organic active layer and the cathode.
[0084] The device can be prepared by a variety of techniques, including sequentially depositing
the individual layers on a suitable substrate. Substrates such as glass and polymeric
films can be used. Conventional vapor deposition techniques can be used, such as thermal
evaporation, chemical vapor deposition, and the like. Alternatively, the organic layers
can be applied by liquid deposition using suitable solvents. The liquid can be in
the form of solutions, dispersions, or emulsions. Typical liquid deposition techniques
include, but are not limited to, continuous deposition techniques such as spin coating,
gravure coating, curtain coating, dip coating, slot-die coating, spray-coating, and
continuous nozzle coating; and discontinuous deposition techniques such as ink jet
printing, gravure printing, and screen printing any conventional coating or printing
technique, including but not limited to spin-coating, dip-coating, roll-to-roll techniques,
ink jet printing, screen-printing, gravure printing and the like.
[0085] The new electroactive compounds described herein can be applied by liquid deposition
from a liquid composition. The term "liquid composition" is intended to mean a liquid
medium in which a material is dissolved to form a solution, a liquid medium in which
a material is dispersed to form a dispersion, or a liquid medium in which a material
is suspended to form a suspension or an emulsion. Any liquid medium in which the compound
is dissolved or dispersed and from which it will form a film can be used. In one embodiment,
the liquid medium consists essentially of one or more organic solvents. In one embodiment
the organic solvent is an aromatic solvent. In one embodiment, the organic liquid
is selected from chloroform, dichloromethane, toluene, anisole, and mixtures thereof.
The new compound can be present in the liquid medium in a concentration of 0.2 to
2 percent by weight. Other weight percentages of the new compound may be used depending
upon the liquid medium.
[0086] In one embodiment, the different layers have the following range of thicknesses:
anode 110, 50-500 nm, in one embodiment 100-200 nm; hole transport layer 120, 5-200
nm, in one embodiment 20-100 nm; photoactive layer 130, 1-200 nm, in one embodiment
10-100 nm; layer 140, 5-200 nm, in one embodiment 10-100 nm; cathode 150, 20-1000
nm, in one embodiment 30-500 nm. The location of the electron-hole recombination zone
in the device, and thus the emission spectrum of the device, can be affected by the
relative thickness of each layer. Thus the thickness of the electron-transport layer
should be chosen so that the electron-hole recombination zone is in the light-emitting
layer. The desired ratio of layer thicknesses will depend on the exact nature of the
materials used.
[0087] In one embodiment, the device has the following structure, in order: anode, buffer
layer, hole transport layer, photoactive layer, electron transport layer, electron
injection layer, cathode. In one embodiment, the anode is made of indium tin oxide
or indium zinc oxide. In one embodiment, the buffer layer comprises a conducting polymer
selected from the group consisting of polythiophenes, polyanilines, polypyrroles,
copolymers thereof, and mixtures thereof. In one embodiment, the buffer layer comprises
a complex of a conducting polymer and a colloid-forming polymeric acid.
[0088] In one embodiment, the hole transport layer comprises the new compound described
herein. In one embodiment, the hole transport layer consists essentially of the new
electroactive compound described herein.
[0089] In one embodiment, the photoactive layer comprises the new electroactive compound
described herein and a photoactive compound. In one embodiment, the photoactive layer
further comprises a second host material. In some embodiments, the photoactive layer
consists essentially of the new electroactive compound described herein and a photoactive
compound. In some embodiments, the photoactive material is present in an amount of
at least 1 % by weight. In some embodiments, the photoactive material is 2-20% by
weight.
[0090] In one embodiment, the electron transport layer comprises a metal complex of a hydroxyaryl-N-heterocycle.
In one embodiment, the hydroxyaryl-N-heterocycle is unsubstituted or substituted 8-hydroxyquinoline.
[0091] In one embodiment, the electron injection layer is LiF or Li
20. In one embodiment, the cathode is Al or Ba/Al.
[0092] In one embodiment, the device is fabricated by liquid deposition of the buffer layer,
the hole transport layer, and the photoactive layer, and by vapor deposition of the
electron transport layer, the electron injection layer, and the cathode.
[0093] Although methods and materials similar or equivalent to those described herein can
be used in the practice or testing of the present invention, suitable methods and
materials are described below. In addition, the materials, methods, and examples are
illustrative only and not intended to be limiting.
EXAMPLES
[0094] The concepts described herein will be further described in the following examples,
which do not limit the scope of the invention described in the claims.
Example 1
[0095] This example illustrates the preparation of a monomer which can be used to form an
electroactive compound, Compound C.
- (a) The starting material ditriflate 1 was synthesized from the scheme described below.

- (b) The monomer 3 was synthesized according to the following scheme:

[0096] In a nitrogen purged glove box, ditriflate
1 (2 g, 2.73 mmol) and 4-octylaniline (1.18 g, 5.73 mmol, 2.1 eq.) were dissolved in
toluene (40 mL) in a 100 mL of round bottom flask, followed by the addition of the
toluene (10 mL) solution of tris(dibenzylideneacetone)dipalladium(0) (25 mg, 0.027
eq.) and 1,1'-bis(diphenylphosphino)ferrocene (30 mg, 0.053 eq) to the mixture. After
stirring the mixture for 5 min, sodium t-butoxide (0.657 g, 6.82 mmol, 2.5 eq) was
added to the resultant solution. The reaction mixture was stirred for 3 days at 90°C
under nitrogen outside glove box. The mixture was passed through a pad of silica gel,
which was rinsed with toluene. The combined solution was concentrated on a rotary
evaporator, followed by flash column chromatography (30% methylene chloride in hexane)
to afford 0.98 g of a white solid as a product. NMR analysis confirmed the structure
of intermediate compound
1.
[0097] In a nitrogen purged glove box, diamine
2 (0.98 g, 1.16 mmol) and 3-bromo-1-iodobenzene (0.99 g, 3.50 mmol) were dissolved
in toluene (30 mL) in a 100 mL of round bottom flask, followed by the addition of
the toluene (8 mL) solution of tris(dibenzylideneacetone)dipalladium(0) (29 mg, 0.027
eq.) and 1,1'-bis(diphenylphosphino)ferrocene (34 mg, 0.053 eq) to the mixture. After
stirring the mixture for 5 min, sodium t-butoxide (280 mg, 2.91 mmol, 2.5 eq) was
added to the resultant solution. The reaction mixture was stirred for 4 days at 90
°C under nitrogen outside glove box. The mixture was passed through a pad of silica
gel, which was rinsed with toluene. The combined solution was concentrated on a rotary
evaporator, followed by flash column chromatography (hexane) to afford 1.2 g of a
white solid. NMR analysis confirmed the structure of compound
3. (polymer H-1661)
Example 2
[0098] The monomer from Example 1 can be polymerized to form Compound C. This can be done
using Yamamoto coupling according to the following scheme:

[0099] All operations were carried out in a nitrogen purged glovebox unless otherwise noted.
Monomer 3 (1.036 g, 0.90 mmol) was added to a scintillation vial and dissolved in
22 mL toluene. A clean, dry 50 mL Schlenk tube was charged with bis(1,5-cyclooctadiene)nickel(0)
(0.500 g, 1.818 mmol). 2,2'-Dipyridyl (0.284 g, 1.818 mmol) and 1,5-cyclooctadiene
(0.197 g, 1.818 mmol) were weighed into a scintillation vial and dissolved in 5.5
mL N,N'-dimethylformamide. The solution was added to the Schlenk tube. The Schlenk
tube was inserted into an aluminum block and the block was heated and stirred on a
hotplate/stirrer at a setpoint that resulted in an internal temperature of 60°C. The
catalyst system was held at 60°C for 30 minutes and then raised to 70°C. The monomer
solution in toluene was added to the Schlenk tube and the tube was sealed. The polymerization
mixture was stirred at 70°C for 18 h. After 18 h, the Schlenk tube was removed from
the block and allowed to cool to room temperature. The tube was removed from the glovebox
and the contents were poured into a solution of conc. HCl/MeOH (1.5% v/v conc. HCl).
After stirring for 2 h, the polymer was collected by vacuum filtration and dried under
high vacuum. The polymer was purified by successive precipitations from toluene into
HCl/MeOH (1 % v/v conc. HCl), MeOH, toluene (CMOS grade), and 3-pentanone. A white,
fibrous polymer (0.200 g) was obtained. The molecular weight of the polymer was determined
by GPC (THF mobile phase, polystyrene standards): M
w=20,486; M
n=5.049; M
w/M
n=4.06. NMR analysis confirmed the structure of Compound C.
Example 3
[0100] This example illustrates the preparation of a monomer which can be used to form an
electroactive compound, Compound D. The monomer
12 was synthesized according to the following scheme:

[0101] In a nitrogen purged glove box, ditriflate
10 (2.72 g, 4.70 mmol) and 4-octylaniline (2.03 g, 9.87 mmol, 2.1 eq.) were dissolved
in toluene (30 mL) in a 100 mL of round bottom flask, followed by the addition of
the toluene (10 mL) solution of tris(dibenzylideneacetone)dipalladium(0) (43 mg, 0.01
eq.) and 1,1'-bis(diphenylphosphino)ferrocene (52 mg, 0.02 eq) to the mixture. After
stirring the mixture for 5 min, sodium t-butoxide (1.13 g, 11.75 mmol, 2.5 eq) was
added to the resultant solution. The reaction mixture was stirred overnight at 85°C
under nitrogen outside glove box. The mixture was passed through a pad of silica gel,
which was rinsed with toluene. The combined solution was concentrated on a rotary
evaporator, followed by flash column chromatography (2% to 10 ethylacetate in hexane,
gradient) to afford 2.37 g of a white solid as a product. NMR analysis confirmed the
structure of intermediate compound
11.
[0102] In a nitrogen purged glove box, diamine
11 (1.45 g, 2.10 mmol) and 3-bromo-1-iodobenzene (1.78 g, 6.3 mmol, 3eq.) were dissolved
in toluene (30 mL) in a 100 mL of round bottom flask, followed by the addition of
the toluene (8 mL) solution of tris(dibenzylideneacetone)dipalladium(0) (52 mg, 0.027
eq.) and 1,1'-bis(diphenylphosphino)ferrocene (62 mg, 0.053 eq) to the mixture. After
stirring the mixture for 5 min, sodium t-butoxide (504 mg, 5.25 mmol, 2.5 eq) was
added to the resultant solution. The reaction mixture was stirred for 3 days at 90°C
under nitrogen outside glove box. The mixture was passed through a pad of silica gel,
which was rinsed with toluene. The combined solution was concentrated on a rotary
evaporator, followed by flash column chromatography (3% toluene in hexane) to afford
1.5 g of a white solid. NMR analysis confirmed the structure of compound
12.
Example 4
[0103] The monomer from Example 3 can be polymerized to form Compound D. This can be done
using Yamamoto coupling according to the following scheme:

[0104] The polymerization of compound 12 performed as described for compound C. The polymer
was obtained as a white solid in 84.6% yield. The molecular weight of the polymer
was determined by GPC (THF mobile phase, polystyrene standards): M
w=1,846; M
n=1,291; M
w/M
n=1.43. NMR analysis confirmed the structure of Compound D.
Example 5
[0105] This example illustrates the preparation of a monomer which can be used to form an
electroactive compound, Compound A. The monomer
15 was synthesized according to the following scheme:

[0106] In a nitrogen purged glove box, ditriflate
13 (1.7 g, 2.33 mmol) and 3-octylaniline (1 g, 4.89 mmol) were dissolved in toluene
(20 mL) in a 100 mL of round bottom flask, followed by the addition of the toluene
(10 mL) solution of tris(dibenzylideneacetone)dipalladium(0) (58 mg, 0.027 eq.) and
1,1'-bis(diphenylphosphino)ferrocene (68 mg, 0.053 eq) to the mixture. After stirring
the mixture for 5 min, sodium t-butoxide (0.56 g, 5.82 mmol, 2.5 eq) was added to
the resultant solution. The reaction mixture was stirred for 16 h at 85°C under nitrogen
outside glove box. The mixture was passed through a pad of silica gel, which was rinsed
with toluene. The combined solution was concentrated on a rotary evaporator, followed
by flash column chromatography (10% to 40% methylene chloride in hexane, gradiently)
to afford 1.6 g of product. NMR analysis confirmed the structure of intermediate compound
14.
[0107] In a nitrogen purged glove box, diamine
14 (1.5 g, 1.78 mmol) and 3-bromo-1-iodobenzene (1.51 g, 5.35 mmol) were dissolved in
toluene (40 mL) in a 100 mL of round bottom flask, followed by the addition of the
toluene (7 mL) solution of tris(dibenzylideneacetone)dipalladium(0) (47 mg, 0.027
eq.) and 1,1'-bis(diphenylphosphino)ferrocene (53 mg, 0.053 eq) to the mixture. After
stirring the mixture for 5 min, sodium t-butoxide (0.428 g, 4.45 mmol, 2.5 eq) was
added to the resultant solution. The reaction mixture was stirred for 4 days at 90°C
under nitrogen outside glove box. The mixture was passed through a pad of silica gel,
which was rinsed with toluene. The combined solution was concentrated on a rotary
evaporator, followed by flash column chromatography (5% toluene in hexane) to afford
1.6 g of a white solid. NMR analysis confirmed the structure of compound
15.
Example 6
[0108] The monomer from Example 5 can be polymerized to form Compound A. This can be done
using Yamamoto coupling according to the following scheme:
The polymerization of compound 15 was performed as described for compound C. The polymer
was obtained as a white solid in 38% yield. The molecular weight of the polymer was
determined by GPC (THF mobile phase, polystyrene standards): Mw=210,638; Mn=33,194; Mw/Mn=6.35. NMR analysis confirmed the structure of Compound A.

Example 7
[0109] This example illustrates the preparation of a monomer which can be used to form an
electroactive compound, Compound B. The monomer
18 was synthesized according to the following scheme:

[0110] In a nitrogen purged glove box, ditriflate
16 (1.67 g, 2.28 mmol) and 4-octylaniline(0.984 g, 4.79 mmol) were dissolved in toluene
(20 mL) in a 50 mL of round bottom flask, followed by the addition of the toluene
(2 mL) solution of tris(dibenzylideneacetone)dipalladium(0) (21 mg, 0.027 eq.) and
1,1'-bis(diphenylphosphino)ferrocene (25 mg, 0.053 eq) to the mixture. After stirring
the mixture for 5 min, sodium t-butoxide (0.548 g, 5.71 mmol, 2.5 eq) was added to
the resultant solution. The reaction mixture was stirred for 20h at 85°C under nitrogen
outside glove box. The mixture was passed through a pad of silica gel, which was rinsed
with toluene. The combined solution was concentrated on a rotary evaporator, followed
by flash column chromatography (25% methylenechloride in hexane) to afford 1.04 g
of a white solid. NMR analysis confirmed the structure of intermediate compound
17.
[0111] In a nitrogen purged glove box, diamine
17 (1.02 g, 1.212 mmol) and 3-bromo-1-iodobenzene (1.029 g, 3.636 mmol) were dissolved
in toluene (20 mL) in a 50 mL of round bottom flask, followed by the addition of the
toluene (2 mL) solution of tris(dibenzylideneacetone)dipalladium(0) (30 mg, 0.027
eq.) and 1,1'-bis(diphenylphosphino)ferrocene (36 mg, 0.053 eq) to the mixture. After
stirring the mixture for 5 min, sodium t-butoxide (291 mg, 3.03 mmol, 2.5 eq) was
added to the resultant solution. The reaction mixture was stirred for 24h at 85°C
under nitrogen outside glove box. The mixture was passed through a pad of silica gel,
which was rinsed with toluene. The combined solution was concentrated on a rotary
evaporator, followed by flash column chromatography (10% toluene in hexane) to afford
1.2 g of a white solid. NMR analysis confirmed the structure of compound
18.
Example 8
[0112] The monomer from Example 7 can be polymerized to form Compound B. This can be done
using Yamamoto coupling according to the following scheme:

[0113] The polymerization of compound 18 was performed as described for compound B. The
polymer was obtained as a white solid in 50% yield. The molecular weight of the polymer
was determined by GPC (THF mobile phase, polystyrene standards): M
w=213,649; M
n=102,594; M
w/M
n=2.08. NMR analysis confirmed the structure of compound B.
[0114] Note that not all of the activities described above in the general description or
the examples are required, that a portion of a specific activity may not be required,
and that one or more further activities may be performed in addition to those described.
Still further, the order in which activities are listed are not necessarily the order
in which they are performed.
[0115] In the foregoing specification, the concepts have been described with reference to
specific embodiments. However, one of ordinary skill in the art appreciates that various
modifications and changes can be made without departing from the scope of the invention
as set forth in the claims below. Accordingly, the specification and figures are to
be regarded in an illustrative rather than a restrictive sense, and all such modifications
are intended to be included within the scope of invention.
[0116] Benefits, other advantages, and solutions to problems have been described above with
regard to specific embodiments. However, the benefits, advantages, solutions to problems,
and any feature(s) that may cause any benefit, advantage, or solution to occur or
become more pronounced are not to be construed as a critical, required, or essential
feature of any or all the claims.
[0117] It is to be appreciated that certain features are, for clarity, described herein
in the context of separate embodiments, may also be provided in combination in a single
embodiment. Conversely, various features that are, for brevity, described in the context
of a single embodiment, may also be provided separately or in any subcombination.
Further, reference to values stated in ranges include each and every value within
that range.